JP3857263B2 - Paper post-processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that is mounted on an image forming apparatus such as a copying machine or a printer and performs stapling or punching on a recording sheet, and an image forming apparatus including the post-processing apparatus.

2. Description of the Related Art Conventionally, a sheet post-processing apparatus that performs post-processing such as stapling or punching on a recording sheet on which a predetermined document image is formed by an image forming apparatus is known. The image forming apparatus and the paper post-processing apparatus are provided with a DC (direct current) motor as a driving means for image forming means such as a photosensitive drum, a paper transport system such as a transport roller, and post-processing means such as a staple device. An overcurrent prevention circuit is provided to stop the supply of current to the DC motor when a current exceeding a predetermined reference current value flows to the DC motor, thereby preventing overheating or damage of the DC motor due to overcurrent. . In addition, when simultaneously driving a drive system such as a sheet conveying roller of an image forming apparatus, there has been proposed one that limits the supply current of each DC motor so that the total value of the supply current to each DC motor does not exceed the power supply capacity. (For example, Patent Document 1).
JP 2003-88185 A

  However, the overcurrent prevention circuit of post-processing means such as a stapling device sets the maximum value of the drive current as the reference current value regardless of the number of recording sheets at the time of processing, so even when the number of recording sheets is small Since the current can be supplied up to the reference current value, there is a problem that excessive current flows to the DC motor when the power supply is turned on or when some abnormality occurs, leading to an increase in power consumption. In addition, since the stapling apparatus has a large load current during driving, other operations of the image forming apparatus and the sheet post-processing apparatus may be restricted during the operation of the stapling apparatus, and the image forming process is inefficient. was there.

  The present invention has been made to solve the above-described problems, and provides a sheet post-processing apparatus and an image forming apparatus that can save power in the post-processing unit and can be simultaneously processed with other apparatuses. For the purpose.

The sheet post-processing apparatus according to claim 1 includes post-processing means for performing stapling processing or punching processing on a recording paper bundle composed of a plurality of recording papers to which an image has been transferred, and driving means for driving the post-processing means. Detection means for detecting that the flowing current exceeds a reference value; and drive control means for stopping the driving means when the detection means detects that the current flowing in the driving means exceeds the reference value; Receiving means for receiving the number information of the recording paper bundle, and a reference value when the number of recording papers indicated in the number information is more than a certain number , selected according to the number information received by the receiving means , and, a setting means for the number of the recording sheets shown to the number information is set to each of the detecting means, a small separate reference value than the reference value when no more than a certain number of sheets, the drive control The stage is connected to a device other than the post-processing unit, and when the setting unit sets the small reference value to the detection unit, the driving unit is driven and the small reference value is set to the detection unit. This is a sheet post-processing apparatus that drives the other apparatus with electric power obtained by the operation . The “post-processing means for performing stapling or punching” includes not only one that performs only one of stapling and punching, but also one that performs both.

The sheet post-processing apparatus according to claim 2, wherein the detection unit includes a plurality of detection units that detect that the current flowing through the drive unit exceeds the reference value, and the detection unit sets a different reference value. are, the setting means is a sheet post-processing apparatus according to claim 1, wherein the setting the detecting means the reference value by selecting a detection portion of a plurality of the detecting portion.

  A sheet post-processing apparatus according to a third aspect is an image forming apparatus including the sheet post-processing apparatus according to the first or second aspect.

  According to a fourth aspect of the present invention, there is provided a sheet post-processing apparatus including a document conveying unit that sequentially conveys a placed document to a reading unit, and an image forming unit that transfers an image of the document read by the reading unit to a recording sheet. The image forming apparatus according to claim 3, further comprising: a sheet number counting unit that counts the number of documents read by the reading unit and outputs the number of documents to the reception unit as the sheet number information.

  According to the present invention, when the post-processing unit is driven, the setting unit changes the reference value, which is a limit value of the current flowing through the driving unit, according to the number of recording paper bundles. Necessary current can be supplied to the drive means, and particularly when the number of recording paper bundles is small, current consumption can be reduced and other devices can be driven simultaneously, so that processing efficiency can be improved.

  A copier as an example of an image forming apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing the internal configuration of the copying machine. The copying machine includes a copying machine main body 1 including an image forming unit 100, a document feeding unit 200, a document reading unit 300, a recording paper transport unit 400, a paper feeding unit 500, and an operation display unit 600. The post-processing apparatus 2 attached to the side part is provided.

  The document reading unit 300 reads a document and generates image data corresponding to the document. The document reading unit 300 includes an unillustrated scanner including a CCD (Charge Coupled Device) sensor that generates image data from an optically acquired document image, an exposure lamp, and the like, and a contact glass 301 and a contact glass on the upper surface thereof. 302. The document reading unit 300 scans a document placed on the contact glass 301 or a document conveyed by the document feeding unit 200 so as to be in contact with the contact glass 302. Output to.

  The document feeding unit 200 feeds a document to the document reading unit 300. The document feeding unit 200 includes a document placement unit 201, a carry-in drive unit 202 including a carry-in roller pair, a conveyance roller pair 203, a discharge roller pair 204, a paper discharge table 205, and a document detection switch 206 that detects the presence or absence of a document. The document placed on the document placement unit 201 is automatically conveyed one by one while being brought into contact with the contact glass 302, and discharged onto the sheet discharge tray 205 after the exposure scanning of the document. Further, the document feeding unit 200 is configured to be retractable, and when the contact glass 301 is lifted upward so as to open the upper surface of the contact glass 301, a read document, for example, a book that is opened in a spread state, is formed on the upper surface of the contact glass 301. Etc. can be placed.

  The paper feed unit 500 includes paper feed cassettes 501 and 502, a manual feed tray 503, and the like. The paper feed cassettes 501 and 502 store recording paper in the copying machine main body 1 for each size. The manual feed tray 503 is configured to be openable and closable at one side portion of the copying machine main body 1, and is used for manually feeding recording paper.

  The recording paper transport unit 400 transports the recording paper fed from the paper feeding unit 500 to the image forming unit 100. The recording paper transport unit 400 is housed in transport paths 401 to 403 for transporting recording paper from the paper feed cassettes 501 and 502 and the manual feed tray 503 to the image forming unit 100, and the paper feed cassettes 501 and 502 and the manual feed tray 503, respectively. Pickup rollers 411 to 413 for taking out the recording paper being fed, paper feed roller pairs 414 to 416 for feeding the taken recording paper one by one to the respective conveyance paths 401 to 403, and recording in each of the conveyance paths 401 to 403 A pair of conveying rollers 417 to 420 for conveying paper is provided.

  The image forming unit 100 forms a predetermined image on the recording paper conveyed by the recording paper conveyance unit 400. The image forming unit 100 includes a photosensitive drum 101 rotatably supported in the direction of the arrow shown in the figure, a charging unit 102, a developing unit 103, a cleaning unit 104 disposed around the photosensitive drum 101, The laser scanning unit 105, the transfer roller 106, the fixing roller pair 107, the conveyance path 108 for conveying the recording paper from the transfer roller 106 to the fixing roller pair 107, and the recording paper from the transfer roller 106 to the discharge tray 120 and the post-processing device 2, respectively. , And a pair of discharge rollers 111 and 112 for discharging the recording paper transported through the transport paths 109 and 110 to the discharge tray 120 and the post-processing device 2, respectively.

  The charging unit 102 uniformly charges the surface of the photosensitive drum 101 to a predetermined potential. The laser scanning unit 105 irradiates the surface of the photosensitive drum 101 with a laser beam based on the image data read by the document reading unit 300 to form an electrostatic latent image on the surface of the photosensitive drum 101. The developing unit 103 makes the image (original image) appear by attaching toner to the electrostatic latent image. The transfer roller 106 transfers the toner image that has been made visible on the photosensitive drum 101 to the recording paper in a state where the conveyed recording paper is pressed against the photosensitive drum 101. The fixing roller pair 107 fixes the toner image transferred to the recording paper. The cleaning unit 104 cleans the toner remaining on the surface of the photosensitive drum 101 after the transfer of the image onto the recording paper is completed.

  The operation display unit 600 is for inputting a predetermined instruction in accordance with a user operation. The operation display unit 600 includes a start key 601 for a user to input a print execution instruction, a numeric keypad 602 for inputting the number of copies to be printed, various operation buttons for inputting various copy operation settings, and the like. And a touch panel 603 including a liquid crystal display (LCD) to be displayed.

  The post-processing device 2 includes a punch unit 701 that performs a punching process as post-processing on the recording paper carried by the discharge roller pair 112, a pair of carrying-in rollers 702 that conveys the recording paper that has been carried in, and the recording paper that has been conveyed. Recording paper tray 703 that temporarily stocks recording paper bundles, two stapling units 704a and 704b that perform stapling as post-processing on the recording paper bundles, and a sort discharge tray that can be moved up and down by a lifting mechanism 705 706, a pair of discharge rollers 707 for discharging the recording paper conveyed from the recording paper receiving tray 703 to the sort discharge tray 706, a non-sort discharge tray 708 disposed on the upper side surface of the post-processing device 2, and a carry-in roller The recording paper conveyance direction from the pair 702 is switched between the recording paper receiving tray 703 side and the non-sort discharge tray 708 side. And a discharge roller pair 710 discharges the recording sheet to the feeding branch guide 709, and the non-sort for the discharge tray 708.

  Further, the post-processing device 2 includes a pair of carry-in rollers 711, 712, and 713 for carrying recording paper into the recording paper receiving tray 703, and movable guide members 714 and 715 for guiding the loading of recording paper into the recording paper receiving tray 703. , 716 and stationary guide portion 717 are provided at different positions with respect to the recording paper loading direction. As a result, the position at which the recording paper having a different size or the recording paper having a different length with respect to the conveyance direction depending on the orientation of the recording paper is carried into the recording paper receiving base 703 is changed according to the size and orientation of each recording paper. By doing so, it is possible to carry the paper into the recording paper receiving tray 703 after aligning the paper in the state in which the ends of the recording paper are aligned.

  In addition, a pair of width adjusting plates 718 are provided at intervals in the width direction of the recording paper receiving tray 703, and a recording paper width adjusting mechanism (not shown) provided on the back side of the recording paper receiving base 703 is used. A width aligning plate 718 is disposed so as to be reciprocally movable in the width direction along the surface of the recording paper receiving tray 703. As a result, the recording paper is carried into the recording paper receiving base 703 while being sandwiched from the left and right by a pair of width adjusting plates 718, and a pair of paper is driven by a width adjusting mechanism driven in accordance with a control signal from the control unit 900 described later. By moving the width adjusting plate 718 inward, the recording sheets can be aligned in the width direction.

  The recording paper receiving base 703 receives and holds the lower end of the recording paper carried into the recording paper receiving base 703, and moves the receiving member in the recording paper carrying-out direction. A drive unit (not shown). Then, when the drive unit is driven in accordance with a control signal from the control unit 900, which will be described later, the recording paper held by the receiving member is conveyed to the discharge roller pair 707 and is sorted by the discharge roller pair 707. It is discharged to 706.

  2 is a perspective view of the recording paper receiving tray 703 shown in FIG. 1, and FIG. 3 is a side sectional view of the recording paper receiving tray 703 shown in FIG.

  Two staple units 704a and 704b are provided below the recording paper receiving tray 703. When stapling is performed on the recording paper stored in the recording paper receiving tray 703, the staple unit 704a is arranged after the end portions in the width direction of the recording paper bundle are aligned by moving the pair of width adjusting plates 718 inward. , 704b bind two ends of the recording paper bundle.

  The staple unit 704a is in contact with, for example, a drive motor 720 that is a DC motor, a support shaft 751 of the drive motor 720, a transfer roller 752 that transmits the driving force of the drive motor 720 to the drive gear 754, and a support shaft 753 of the transmission roller 752. , A driving gear 754 that is rotated by the driving force of the driving motor 720 transmitted by the transmission roller 752, a cam 755 that is coupled to the driving gear 754 and that rotates in conjunction with the rotation of the driving gear, and is moved up and down by the rotation of the cam 755. A stapling portion 757 having a swingable root portion 756 and performing a staple driving operation on a recording paper bundle placed on the recording paper receiving base 703 in conjunction with the rotation of the cam 755 is provided. Since the configuration of the staple unit 704b is the same, illustration and description thereof are omitted here.

  FIG. 4 is a block diagram showing the configuration of the drive mechanism and control unit of the staple units 704a and 704b.

  The drive mechanism of the staple unit 704a includes a drive motor 720, a motor driver 722, a current / voltage conversion unit 724, and three overcurrent detection units 726 to 728. The motor driver 722 supplies current to the drive motor 720 and rotates it in the forward direction or the reverse direction. The current / voltage conversion unit 724 detects the current from the drive motor 720 and converts it into a voltage. The overcurrent detection units 726 to 728 have reference voltage storage units 732 to 734 that store a reference voltage value that is a limit value of the current supplied to the drive motor 720, and are detected by the reference voltage value and the current / voltage conversion unit 724. When the detected voltage value exceeds the reference voltage value, an overcurrent detection signal is output to the drive control unit 904. The reference voltage value stored in the reference voltage storage unit 732 is a voltage value corresponding to 1 A (ampere), the reference voltage value stored in the reference voltage storage unit 733 is a voltage value corresponding to 3 A, and the reference voltage storage The reference voltage value stored in the unit 734 is a voltage value corresponding to 6A. The drive mechanism of the staple unit 704b includes a drive motor 721, a motor driver 723, a current / voltage conversion unit 725, and three overcurrent detection units 729 to 731. The functions of each unit are the same as those of the staple unit 704b. Is omitted. Here, three overcurrent detection units 726 to 731 are provided for each of the staple units 704a and 704b. However, the number of staple units and overcurrent detection units is not limited to this and can be changed. It is.

  The controller 900 is connected to the drive mechanism of each staple unit 704a, 704b. The control unit 900 includes a ROM (Read Only Memory) that stores a control program, a RAM (Random Access Memory) that temporarily stores data, a microcomputer that reads and executes the control program from the ROM, and the like. A staple control unit 901 and a storage unit 907 are provided to control the drive mechanism of the staple units 704a and 704b. The control unit 900 is connected to the image forming unit 100, the document feeding unit 200, the document reading unit 300, the recording paper transport unit 400, the paper feeding unit 500, the operation display unit 600, and the like shown in FIG. An image formation control unit 906 that controls each unit of the machine main body 1 is provided.

  The staple control unit 901 includes a copy number storage control unit 902, a document number counting unit 903, and a drive control unit 904.

  The copy number storage control unit 902 stores the copy number input by the numeric keypad 602 of the operation display unit 600 in the copy number storage unit 908. The document number counting unit 903 conveys documents placed on the document placing unit 201 one by one to the document reading unit 300 by the conveyance roller pair 203 and the like, and the document reading unit 300 reads image data from the document. Each time the count number is incremented by 1, the number of documents is obtained, and the obtained number of documents is stored in the document number storage unit 909. The drive control unit 904 outputs a drive signal to either or both of the motor drivers 722 and 723 when the staple mode is selected. In addition, when the staple unit 704a is driven, the drive control unit 904 selects any of the overcurrent detection units 726 to 728 according to the number of documents stored in the document number storage unit 909, outputs a drive signal, and the staple unit 704b. During driving, one of the overcurrent detection units 729 to 731 is selected according to the number of documents stored in the document number storage unit 909, and a drive signal is output.

  FIG. 5 is a flowchart for explaining processing by the control unit in the staple mode.

  When the staple mode is selected from a function list screen (not shown) for selecting various functions displayed on the touch panel 603 (Yes in step S1), the process proceeds to step S3, and the copy number storage control unit 902 operates the operation display unit. It is determined whether or not the number of copies has been input by the numeric keypad 602 of 600 (step S3). When the number of copies has been input, the number of copies input by the copy number storage control unit 902 is stored in the copy number storage unit 908. On the other hand, if the number of copies is not input, it is determined that the number of copies is one which is an initial value, and 1 is stored in the number-of-copies storage 908 (step S7).

  When the start button is pressed in step S9, the process proceeds to step S11, where it is determined whether or not the document is set on the document placement unit 201 by the document detection switch 206, and the document is set on the document placement unit 201. In step S13, a scan start instruction is output from the image forming control unit 906 to the document feeding unit 200 and the document reading unit 300, and the document stored in the document placement unit 201 is transferred by the conveyance roller pair 203 or the like. While being transported onto the contact glass 302, the document reading unit 300 sequentially reads the image data of the document. Simultaneously with the reading of the document image data by the document reading unit 300, the count number is incremented by 1 by the document number counting unit 903 (step S15), and when the image data reading operation by the document reading unit 300 ends (Yes in step S17). The document number counted by the document number counting unit 903 is stored in the document number storage unit 909 (step S23). If the document is not set on the document placement unit 201, it is assumed that the document is placed on the contact glass 301, and the image formation control unit 906 instructs the document reading unit 300 to start scanning (step S19). The original image data is read by the original reading unit 300, and 1 is set as the number of originals by the original number counting unit 903 (step S21) and stored in the original number storage unit 909 (step S23). ).

  Next, when an image formation start instruction is output from the image formation control unit 906 to the image formation unit 100 (step S25), the image formation unit 100 performs an image formation process based on the image data, and the image formation control unit. A conveyance path instruction signal for conveying the recording paper from 906 to the post-processing device 2 is output to the image forming unit 100 (step S27), and the recording paper onto which the image has been transferred is sequentially sent to the post-processing device 2 by the discharge roller pair 110. The recording paper is discharged, and is loaded into the recording paper receiving tray 703 by the carrying-in roller pair 702 and the receiving tray loading rollers 711 to 713 and stocked.

  When the image forming unit 100 completes the image forming process for one document (Yes in step S29), the drive control unit 904 determines whether or not the number of documents stored in the document number storage unit 909 is less than 20. In step S31, if the number of documents is less than 20, the drive control unit 904 selects the overcurrent detection units 726 and 729 in which the minimum reference voltage is set from the overcurrent detection units 721 to 731. In addition, a drive signal is output to each of them (step S33), and a drive signal is simultaneously output to the motor drivers 722 and 723 (step S35). As a result, both the staple units 704a and 704b are driven at the same time to perform two-point binding at the end of the recording paper. During the staple driving operation of each of the staple units 704a and 704b, each of the overcurrent detection units 726 and 729 outputs a voltage value corresponding to the current value flowing from the motor drivers 722 and 723 to the drive motors 720 and 721 to the current / voltage conversion unit 724. , 725, and the detected voltage value is compared with the reference voltage value stored in each reference voltage storage unit 732, 735, and if the detected voltage value exceeds the reference voltage value, it is determined that the current is overcurrent, and driving An overcurrent detection signal is output to the control unit 904. The drive control unit 904 determines whether or not an overcurrent detection signal has been received from the overcurrent detection units 726 and 729. When the drive control unit 904 receives the overcurrent detection signal (step S47), each drive from the motor drivers 722 and 723 is performed. A drive signal for turning off the current supply to the motors 720 and 721 is output to the motor drivers 722 and 723 (step S49), and the rotation of the drive motors 720 and 721 is stopped.

  If the number of documents exceeds 20, the drive control unit 904 further determines whether or not the number of documents is less than 40 (step S37). If the number of documents is less than 40, the drive control unit 904 As a result, the overcurrent detection units 727 and 730 are selected, the drive signals are output to each of them (step S39), and the drive signals are simultaneously output to the motor drivers 722 and 723 (step S41). As a result, both the staple units 704a and 704b are driven at the same time to perform two-point binding at the end of the recording paper. During the staple driving operation of each staple unit 704a, 704b, each overcurrent detection unit 727, 730 is stored in the detected voltage value obtained by the current / voltage conversion unit 724, 725 and each reference voltage storage unit 733, 736. When the detected voltage value exceeds the reference voltage value, it is determined that there is an overcurrent, and an overcurrent detection signal is output to the drive control unit 904. When the drive control unit 904 receives the overcurrent detection signals from the overcurrent detection units 727 and 730 (Yes in step S47), the drive control unit 904 sends a drive signal for turning off the current supply to the drive motors 720 and 721 to each motor. It outputs to the driver 722,723 (step S49), and rotation of each drive motor 720,721 is stopped.

  When the number of documents exceeds 40, the drive control unit 904 selects the overcurrent detection units 728 and 731 having the maximum reference voltage value from the overcurrent detection units 721 to 731, and the drive signal is transmitted to each of them. In addition to the output (step S43), a drive signal is output only to the motor driver 722, and the staple unit 704a performs a binding process at one end of the recording paper bundle. After the staple processing by the staple unit 704a is completed, a drive signal is output from the drive control unit 904 to the other motor driver 723, and the staple processing of the recording paper bundle end by the staple unit 704b is performed. Binding ends (step S45). At the time of stapling operation of each staple unit 704a, 704b, each overcurrent detection unit 728, 731 is stored in the detected voltage value obtained by the current / voltage conversion unit 724, 725 and each reference voltage storage unit 734, 737. The reference voltage value is compared, and if the detected voltage value exceeds the reference voltage value, it is determined that the current is an overcurrent, and an overcurrent detection signal is output to the drive control unit 904. When the drive control unit 904 receives an overcurrent detection signal from the overcurrent detection units 728 and 731 (Yes in step S47), the drive control unit 904 sends a drive stop signal for turning off the current supply to the drive motors 720 and 721 to each motor. It outputs to the driver 722,723 (step S49), and rotation of each drive motor 720,721 is stopped.

  Next, a transport instruction signal for transporting the recording paper to the sort discharge tray 706 is output from the image forming control unit 906 to the post-processing device 2 (step S51), and the drive unit of the receiving member is driven. The recording paper bundle stored in the recording paper receiving tray 703 is conveyed to the discharge roller pair 707 and discharged to the sorting discharge tray 706 by the discharge roller pair 707. The image formation control unit 906 determines whether printing for the number of copies stored in the copy number storage unit 908 has been completed (step S53). If printing for all the numbers has not been completed, the process returns to step S25. If finished, the process is terminated.

  As described above, in the present embodiment, among the plurality of overcurrent detection units 726 to 731 having different reference voltages according to the number of recording paper bundles when the driving motors 720 and 721 of the staple units 704a and 704b are driven. Since any one of the overcurrent detection units is selectively used, the limit value of the current flowing through each of the drive motors 720 and 721 is switched according to the number of recording paper bundles, and the necessary load current according to the number of recording paper bundles Can be supplied to the drive motors 720 and 721. In particular, when the number of recording paper bundles is small, current consumption can be reduced and other devices can be driven simultaneously, so that processing efficiency can be improved. In addition, when the number of recording paper bundles is large, the stapling processes by the stapling units 704a and 704b are performed separately without being performed at the same time, so that overcurrent can be prevented and other devices can be driven simultaneously, thereby improving processing efficiency. be able to.

  In the present embodiment, a plurality of overcurrent detection units 726 to 731 are provided for the drive motors 720 and 721 of the staple units 704a and 704b, respectively, and the drive motors 720 according to the number of recording paper bundles to be stapled. , 721 of the supply current limit value is switched, each staple unit 704a, 704b is provided with one overcurrent detection unit having a plurality of different reference voltages, and the reference voltage is switched according to the number of recording paper bundles. It may be configured.

In this embodiment, the staple units 704a and 704b are used. However, the present invention is not limited to this. The punch unit performs a punching process on a recording paper bundle composed of a plurality of recording papers to which an image has been transferred . The present invention can also be applied to an apparatus having a large variation, and in the combination of the staple units 704a and 704b and the punch unit , the simultaneous processing of the staple processing and the punch processing can be performed or prohibited according to the limit value of each driving current. The operation timing of each device may be set.

1 is a side sectional view showing an internal configuration of a copying machine that is an example of an image forming apparatus according to an embodiment of the present disclosure. FIG. 2 is a perspective view of the recording paper tray shown in FIG. 1. FIG. 2 is a side sectional view of the recording paper receiving tray shown in FIG. 1. It is a block diagram which shows the structure of the drive mechanism and control part of a staple unit. It is a flowchart for demonstrating the process by the control part at the time of a staple mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming part 200 Original feeding part 300 Original reading part 400 Recording paper conveyance part 500 Paper feed part 600 Operation display part 704a, 704b Staple unit 720,721 Driving motor 722,723 Motor driver 724,725 Current / voltage conversion part 726 -731 Overcurrent detection unit 732-737 Reference voltage storage unit 900 Control unit 901 Staple control unit 902 Copy number storage control unit 903 Document number count unit 904 Drive control unit 906 Image formation control unit 907 Storage unit 908 Copy number storage unit 909 Document Number storage unit

Claims (4)

Post-processing means for performing stapling or punching on a bundle of recording paper comprising a plurality of recording papers to which an image has been transferred;
Detecting means for detecting that the current flowing through the driving means for driving the post-processing means exceeds a reference value;
A drive control means for stopping the drive means when the detection means detects that the current flowing through the drive means exceeds the reference value;
Receiving means for receiving information on the number of sheets of recording paper bundle;
The reference value when the number of recording sheets indicated by the number information exceeds a certain number , selected according to the number information received by the receiving means , and the number of recording sheets indicated by the number information are constant. when not exceeding the number, and a setting means for setting a small separate reference value than the reference value to each of the detecting means,
The drive control means is connected to a device other than the post-processing means, and when the setting means sets the small reference value to the detection means, the drive means is driven and the small reference value is detected by the detection means. A sheet post-processing apparatus that drives the other apparatus with electric power obtained by being set in the means . The detection unit includes a plurality of detection units that detect that the current flowing through the drive unit exceeds the reference value , and each of the detection units is set with a different reference value.
The sheet post-processing apparatus according to claim 1, wherein the setting unit sets the reference value in the detection unit by selecting a detection unit from a plurality of the detection units.   An image forming apparatus comprising the sheet post-processing apparatus according to claim 1. A document conveying means for sequentially conveying the placed document to the reading unit;
Image forming means for transferring an image of the document read by the reading unit onto a recording sheet,
4. The image forming apparatus according to claim 3, further comprising a sheet number counting unit that counts the number of documents read by the reading unit and outputs the number of documents to the receiving unit as the number information.

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